Observations on the ureteropelvic junction

Variations in the Density and Distribution of Cajal Like Cells Associated With the Pathogenesis of Ureteropelvic Junction Obstruction: A Systematic Review and Meta-Analysis

Introduction: Cajal like cells (CLCs) in the upper urinary tract have an ability to generate coordinated spontaneous action potentials and are hypothesized to help propel urine from renal pelvis into the ureter. The objective of this review was to describe the variations in the density and distribution of CLCs associated with ureteropelvic junction obstruction (UPJO). Materials and Methods: Studies comparing the density and distribution of CLCs in the human upper urinary tract in patients with UPJO and healthy controls were included in this systematic review. We searched online electronic databases; Ovid MEDLINE, Scopus, PubMed and Cochrane reviews for the studies published before October 31, 2020. A meta-analysis was conducted to compare the density of CLCs at the ureteropelvic junction (UPJ) in patients with UPJO and matched controls. Results: We included 20 and seven studies in the qualitative and quantitative synthesis, respectively. In majority (55%) CLCs were located between the muscle layers of the upper urinary tract. The CLC density in the UPJ gradually increased with aging in both healthy subjects and patients with UPJO. The pooled analysis revealed that the density of CLCs at the UPJ was significantly low in patients with UPJO compared to the controls (SMD = -3.00, 95% CI = -3.89 to -2.11, p < 0.01). Conclusions: The reduction in CLC density at the UPJ in patients with UPJO suggests a contribution from CLCs in the pathogenesis of UPJO. Since age positively correlates with CLC density, it is imperative to carefully match age when conducting case control studies comparing the CLC density and distribution. Protocol Registration Number: CRD42020219882.

The search for the definition, etiology, and effective diagnosis of upper urinary tract obstruction: the Whitaker test then and now

INTRODUCTION

Robert Whitaker, inspired by Dr William W Scott at the Brady Institute at Johns Hopkins and by Sir David Innes Williams at Great Ormond Street Hospital for Children in the late 1960s, spent much of his career exploring the meaning of persistent dilatation of the upper urinary tract, in an attempt to define obstruction and to find a means of diagnosing it accurately.

OBJECTIVE

This is a historical review of Bob Whitaker's journey from his definition of obstruction to the inception of his eponymous test.

RESULTS

In 1975, he proposed a theory to explain the pathophysiology behind obstructive hydronephrosis and megaureter. He was among the first pediatric urologists to observe that 'it is wrong… to assume that dilatation necessarily indicates obstruction', a statement that was widely stated and even appeared in the textbooks at the time. He defined obstruction as 'an increased pressure in the pelvicalyceal system of the kidney at normal physiological flow rates such that the renal function is adversely affected'. This realization led to the development of a percutaneous pressure-measuring technique at controlled flows, later referred to as the Whitaker test. It predated and later assisted in the interpretation of diuretic renograms.

DISCUSSION

Whitaker questioned the etiology of 'hydronephrosis' and challenged other hypotheses proposed at the time, which often included causes of mechanical occlusion at the ureteropelvic junction (UPJ) or ureterovesical junction (UVJ). Whitaker's hypothesis is that 'obstruction' at UPJ and UVJ levels is not mechanical but the result of a failure of normal peristalsis to form and propagate a bolus. This, in turn, depends on the potentially abnormal distensibility of the renal pelvic and ureteric wall whether it be congenital or acquired. The aim of this review is to recall the history of the development of a technique to evaluate dilated upper urinary tracts and to re-evaluate various theories that might explain the etiology of the dilatation in the light of more recent evidence. Robert (or Bob, to his colleagues) Whitaker was among the founder members of the British Association of Paediatric Urologists, which now has more than 50 members, in 1992. Together with his colleagues Philip Ransley and David Thomas, Whitaker established the annual pediatric urology course for pediatric surgery and urology trainees in Cambridge, U.K., which still runs to this day. He retired from his surgical practice in 1990 and up until the present time has taught clinical anatomy in the Cambridge University School of Medicine.

Intraoperative inspection of the ureteropelvic junction during pyeloplasty is not sufficient to distinguish between extrinsic and intrinsic causes of obstruction: Correlation with histological analysis

INTRODUCTION

Based on current knowledge, it is possible to have an initial diagnosis of intrinsic or extrinsic ureteropelvic junction obstruction (UPJO) based solely on clinical and imaging findings. However, it may not be possible to strictly discriminate an intrinsic case with an additional extrinsic component from a primarily intrinsic stenosis because of lower pole aberrant vessels. These two disorders may coexist or trigger each other. Herein, we aimed to compare the histological changes observed in intrinsic and extrinsic types of UPJO. Our hypothesis is that inspecting the UPJ during pyeloplasty may not be a sufficient way to delineate the underlying cause of obstruction in every individual.

MATERIAL AND METHODS

We retrospectively reviewed the data of 56 patients who had dismembered pyeloplasty. The intrinsic and extrinsic groups consisted of 38 and 18 patients, respectively. Masson's trichrome stain, CD117, and connexin 43 (Cx43) antibody were used in histopathology and immunochemistry. Statistical calculations were done with chi-square and Mann-Whitney U tests.

DISCUSSION

Connexin 43 staining pattern, CD117 positive cell count, and the extent of fibrosis did not differ significantly between extrinsic and intrinsic cases. However, the difference with regard to the degree of muscular hypertrophy was close to statistical significance. The exact pathophysiological mechanism underlying UPJO has yet to be elucidated. A study directly comparing both groups histologically is indeed rare. Our study showed that there are no significant differences between the intrinsic and extrinsic groups in terms of the pacemaker activity, gap junctional communication, and extent of fibrosis. Muscular hypertrophy, which was marginally higher in our extrinsic group, may persist despite successful relocation of the obstructing vessel. The main drawbacks of our study are; the absence of a control group and the retrospective study design with its inherent selection biases.

CONCLUSIONS

Immunohistochemical profiles of intrinsic and extrinsic UPJOs resemble each other. Intraoperative inspection of the UPJ may not be enough for accurate discrimination for a surgical procedure that can correct only the extrinsic cause.

Differences between intrinsic and extrinsic ureteropelvic junction obstruction related to crossing vessels: histology and functional analyses

PURPOSE

In children, ureteropelvic junction obstruction (UPJO) is mostly caused by intrinsic factors (IUPJO); extrinsic UPJO are rare and often due to crossing vessels (CVs).

METHODS

We retrospectively reviewed all data of children with UPJO that underwent surgery in our institution from 2004 to 2011. Analyses included age at surgery, gender, preoperative and postoperative results of ultrasound and renal scans [differential renal function (DRF); signs of obstruction], and pathology reports. Available histological specimens of cases with CV were compared to a random selection of intrinsic cases in a blinded fashion. After additional Masson's trichrome staining, the specimens were scored for fibrosis, muscular hypertrophy, and chronic inflammation.

RESULTS

Out of 139 patients with UPJO, 39 cases were associated with CV. Median age at surgery was 68 months (range 2-194) in the CV group and 11.5 months (range 0-188) in IUPJO group. Laparoscopic dismembered pyeloplasty (LDMP) was carried out in 134 and open DMP in five patients. Preoperative ultrasound identified 28/39 cases with CV. DRF below 40 % was more frequently seen in CV patients (p = 0.020). Histological analyses revealed no differences between the CV and IUPJO specimens in total. CV patients with higher grades of muscular hypertrophy had lower preoperative DRF, compared to those with higher preoperative DRF (p = 0.026). Functional recovery after (L)DMP was excellent in both groups.

CONCLUSION

We could not find any significant histological differences between CV and IUPJO in children. To obtain excellent functional recovery, surgical procedures with a definite correction of the UPJ should be preferred in paediatric patients with CV.

Is the pelviureteric junction an anatomical entity?

OBJECTIVE

The concept of the pelviureteric junction has existed for more than a century and yet there is no clear anatomical definition of this junction. This systematic review addresses the question of whether the human pelviureteric junction is a discrete anatomical entity.

METHODS

A systematic literature review was undertaken to investigate the normal gross and microscopic anatomy of the pelviureteric junction using the electronic databases MEDLINE, PubMed, Cochrane Library and Google Scholar.

RESULTS

In most individuals there is a gradual transition between the renal pelvis and ureter with no external features indicating the presence of a discrete pelviureteric 'junction'. Internally, however, luminal mucosal folds are prominent in this region. There is no consensus on the arrangement of muscle fibers at the pelviureteric junction (which may be age-dependent) although some studies suggest a focal thickening in the muscle wall consistent with physiological observations suggesting a high pressure zone capable of regulating urine flow. Studies of innervation have shown no evidence of specialization at this site.

CONCLUSIONS

There is some evidence that a pelviureteric region can be delineated anatomically and physiologically. However, although it may be a useful clinical concept, there is no sound anatomical basis for an actual pelviureteric junction.

Pathologic findings in patients with ureteropelvic junction obstruction and crossing vessels

OBJECTIVES

To define the role of crossing vessels in the pathophysiology of ureteropelvic junction (UPJ) obstruction, we analyzed the relationship between the presence of crossing vessels and UPJ pathologic findings in patients undergoing laparoscopic pyeloplasty. The significance of crossing renal vessels in patients with UPJ obstruction is unclear.

METHODS

We performed a retrospective analysis of 155 consecutive patients undergoing laparoscopic pyeloplasty. Pathologic specimens from the UPJ were evaluated in 95 patients. The presence or absence of crossing vessels was documented intraoperatively. The histopathologic findings allowed for categorization into 5 groups: group 1, normal ureteral tissue; group 2, chronic inflammation; group 3, smooth muscle hypertrophy, group 4, fibrosis; and group 5, smooth muscle atrophy. The pathologic findings between patients with and without crossing vessels were compared.

RESULTS

Overall, crossing vessels were identified in 98 patients (63.2%). Of the 95 cases with specimens retrieved for histologic analysis, 65 had crossing vessels and 30 did not. The most common UPJ histologic finding in patients with crossing vessels was no intrinsic abnormality (43%). In contrast, this was seen in only 10% of patients without a crossing vessel. In the group without crossing vessels, chronic inflammation (40%) was the predominant histologic findings. Patients with a crossing vessel were less likely to have intrinsic histologic pathologic findings (P < .0003).

CONCLUSIONS

Patients with crossing vessels and UPJ obstruction had no histologic abnormalities identified in 43% of cases. This finding implicates crossing vessels in the pathogenesis of select cases of UPJ obstruction and direct mechanical compression as the etiology of obstruction in these individuals.

Upper urinary tract dilatation: prenatal diagnosis, management and outcome

Upper urinary tract dilatation is one of the most common abnormalities detected on prenatal ultrasound scanning. It is commonly due to transient urine flow impairment (UFI) at the level of the pelvi-ureteric and vesico-ureteric junctions, which improves with time in most cases. It is usually in the neonatal period that the diagnosis is confirmed and during the first 18 months of life that the prognosis of the dilatation is defined.

Pathophysiology and treatment of ureteropelvic junction obstruction

This paper reviews the current literature on both the pathophysiology and treatment options for ureteropelvic junction obstruction (UPJO). A medical literature search using Pubmed/Medline that addressed both the pathophysiology of UPJO and the different treatment options for the adult and pediatric population with UPJO was performed. The pathophysiology of UPJO is still unknown but appears to be multifactorial. Perhaps future molecular studies will give us an answer to the etiology and also a pathway in preventing UPJO. Treatment options have been studied in-depth, and the gold standard is open pyeloplasty. In both the pediatric and adult population, laparoscopic or robotic pyeloplasty has similar success rates to open pyeloplasty with the benefits of minimally invasive surgery. In the pediatric population, however, further studies need to be done. Endopyelotomy also has a role in the treatment of UPJO but should have strict selection criteria.

Collagen Changes in the Ureteropelvic Junction after Failed Antegrade Endopyelotomy

PURPOSE

We evaluated the collagen content and differentiation of the ureteropelvic junction (UPJ) of patients who underwent Anderson-Hynes dismembered pyeloplasty after failure of antegrade endopyelotomy.

MATERIALS AND METHODS

A total of 12 UPJ obstructions were examined more than 12 months after endopyelotomy with both histochemical staining to analyze total collagen content and immunohistochemical staining to analyze collagen types I and III. The specimens were compared with 12 primary UPJ obstructions and 6 normal UPJs. Statistical analysis was performed using Fisher's test and Wilcoxon matched-pairs signed-rank test.

RESULTS

Immunohistochemical staining revealed that collagen type I was located in the interfascicular space and collagen type III in the intrafascicular space in all UPJs. We found more collagen in obstructed than in normal UPJs. Collagen type III was more abundant in secondary than in primary UPJ obstructions (P < 0.01). In obstruction after endopyelotomy, the staining intensity of collagen type III was greater than the intensity of collagen type I (P < 0.01).

CONCLUSION

Our results suggest that the success of antegrade endopyelotomy was impaired by an inflammatory process. This condition determined a shift of collagen differentiation toward type III, which is more fibrous than type I.

A case of Crohn's disease with hydronephrosis caused by ureteropelvic junction obstruction

Ureteral obstruction is a rare extraintestinal manifestation of Crohn's disease (CD). We report the case of a 20-year-old man who presented with fever, diarrhoea, and lower abdominal pain. Diagnostic studies confirmed CD and revealed an abdominal mass obstructing the right ureter and hydronephrosis. Ureteropelvic junction (UPJ) obstruction was diagnosed. Despite an elemental diet and mesalazine therapy, the hydronephrosis persisted, and the patient eventually required surgery. Successful laparoscopic pyeloplasty was performed. This is the first report of CD associated with UPJ obstruction. Ureteral obstruction as a complication of CD is discussed.

Defective in vitro contractility of ureteropelvic junction in children with functional and obstructive urine flow impairment

BACKGROUND/PURPOSE

Studies of children with urinary flow impairment (UFI) at the ureteropelvic junction (UPJ) have revealed prestenotic, stenotic, and poststenotic histologic changes. Muscle function, however, has not been investigated. We therefore evaluated in vitro UPJ contractility by tensiometry in children with UFI.

METHODS

Freshly excised UPJs from 11 children with UFI (6 functional, 5 obstructive) were each divided into 3 parallel, prestenotic, stenotic, and poststenotic rings, and those from 7 children with Wilms' tumor were divided into proximal, medial, and distal segments. Each ring was studied in vitro by tensiometry in the basal state and after stimulation with 25 and 60 mmol/L KCl.

RESULTS

The stenotic rings from the UFI subjects displayed a significantly lower basal contractility than the other 2 rings, and their 25 and 60 mmol/L KCl-induced contractility was absent or severely reduced, whereas the values of these parameters were similar to that observed in controls in the other 2 rings of patients with either functional or obstructive UFI.

CONCLUSIONS

Basal and KCl-induced contractility of the stenotic segment is severely impaired in children and infants with either functional or obstructive UFI, whereas the contractility of their pre- and poststenotic UPJ segments is similar to that recorded in controls.

Glial cell line-derived neurotrophic factor and synaptophysin expression in pelviureteral junction obstruction

OBJECTIVES

To examine the expression of neuronal markers in congenital pelviureteral junction (PUJ) obstruction as a causative factor. The findings from some investigations have suggested that defective neuronal innervation may play an important role in the pathogenesis of PUJ obstruction.

METHODS

Using specific antibodies, we studied the neuronal markers of specimens from 12 cases of PUJ obstruction and 10 normal PUJs by immunohistochemistry using glial cell line-derived neurotrophic factor (GDNF), synaptophysin, S-100, and neurofilament.

RESULTS

In the PUJ obstruction specimens, staining with hematoxylin-eosin and Masson's trichrome revealed muscular hypertrophy and an increase in collagen tissue and fibrosis in the lamina propria and tunica muscularis. The most striking finding on immunohistochemistry was the marked nuclear staining of cells with synaptophysin in all layers of the PUJ obstruction specimens that was totally absent in the normal PUJ specimens. In addition, significantly less intense staining for GDNF was found in the PUJ obstruction specimens compared with the normal PUJ specimens. The underexpression of GDNF in PUJ obstruction specimens was localized in the muscular layer especially. Immunohistochemical staining for S-100 and neurofilament showed no differences in the expression level of these neuronal markers in normal and PUJ obstruction specimens.

CONCLUSIONS

Because GDNF is a survival factor for central and peripheral neurons, defective expression of GDNF could play an important role in the defective neuronal innervation of PUJ obstruction. Intense nuclear expression of synaptophysin in all layers of obstructed PUJ specimens suggested that obstructed PUJs have a serious structural abnormality.

Renal imaging: what the urologist wants to know

Preoperative imaging in renal surgery is of utmost importance in contemporary surgical practice. From a diagnostic standpoint, imaging discovers many renal tumors incidentally before they become symptomatic. These tumors often are amenable to partial renal resection or minimally invasive surgical approaches. In general, surgical interventions for renal abnormalities have evolved to a less invasive endourologic or laparoscopic approach. Selection of the appropriate surgical intervention for renal tumors, collecting system tumors, and hydronephrosis depends heavily on the anatomy of the renal pathology. Thus, renal imaging is crucial in clinical decision-making. This article reviews the contribution of imaging to the surgical management of renal tumors, upper tract urothelial tumors, and ureteropelvic junction obstruction.

Partial unilateral ureteral obstruction in rats

This review comprises an overview of the current knowledge on experimental partial unilateral ureteral obstruction (PUUO) and a summary of our latest original experimental PUUO studies in rats. Neonatal PUUO is the type of obstruction that is most often encountered in pediatric clinical practice. However, the pathogenesis of PUUO is still incompletely understood. Most of our knowledge on PUUO has been derived from experimental studies in a variety of animal models. Although progress has been made, the natural history of congenital hydronephrosis is still incompletely described. The effects on kidney functions of long-term urinary tract obstruction, especially PUUO, have been less intensively studied. Recently, we created models with mild and severe PUUO in young rats by embedding the upper one fourth or the upper two thirds of the left ureter into the psoas muscle, respectively. Thereafter, the technique was used to create mild and severe PUUO in newborn rats and magnetic resonance imaging studies showed that both mild and severe obstruction caused a time-dependent decrease in renal blood flow. Compensatory increase in total kidney volume and renal vein blood flow in contralateral non-obstructed kidneys was not detectable when functional deterioration in the partially obstructed kidneys was present. Finally, we investigated the dynamic changes in renal relative signal intensity (RSI) of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) using magnetic resonance imaging in rats with partial, complete unilateral ureteral obstruction and sham-operated controls. The results showed that changes in Gd-DTPA RSI are compatible with the known physiological and anatomical changes in kidneys in response to ureteral obstruction and useful for distinguishing an obstructed from a non-obstructed collecting system and also for differentiating a partially obstructed from a completely obstructed collecting system.

How they begin and how they end: classic and new theories for the development and deterioration of congenital anomalies of the kidney and urinary tract, CAKUT

CAKUT are problems that often require surgical intervention or, in the worst case, lead to renal failure and the need for dialysis and/or renal transplantation. It is believed that these anomalies share a common genetic cause and to date there has been no good animal model with which to study these abnormalities. Although the abnormal interaction between the ureteral bud and metanephric blastema leads to renal hypodysplasia, vesicoureteral reflux, and ectopic ureters to name a few, the genetic and biochemical modulation of urinary tract development is not understood. Studies using the mouse strain mutant for angiotensin type 2 (AT2) receptors have given new insight into this mystery. The animals show defective apoptosis of undifferentiated mesenchymal cells in the area surrounding the developing kidney and urinary tract. This abnormal apoptosis may well interfere with the normal interaction between the ureteral bud and metanephric blastema resulting in CAKUT. This abnormal interaction would theoretically lead to preexisting intrinsic abnormalities of the kidney, which are programmed and take effect early in embryonic development. In the worst cases, the renal abnormalities would lead to progressive deterioration of renal function. Undoubtedly, there are more genes and biochemical modulators involved in this process other than the RAS and AT2 receptors. Our current animal model gives new and unique possibilities with which to study development of the kidney and urinary tract and ultimately seek ways of preventing an often debilitating disease process.

Crossing vessels. Endourologic implications

The controversy regarding the functional significance of vessels crossing at the ureteropelvic junction is not a new one, though this debate has been resurrected in recent years because of application of endourologic techniques to manage ureteropelvic junction (UPJ) obstruction. The principle limitation of endoscopic treatment of UPJ obstruction is the inferior success rate compared to open dismembered pyeloplasty. The influence crossing vessels may have in affecting both the success rates and complications of endoscopic treatment of UPJ obstruction has yet to be resolved. Crossing vessels may be important for two reasons: (1) they are a potential source of hemorrhage following endoscopic incision, and (2) they may play an etiologic role in UPJ obstruction and therefore may be a reason for failure of endoscopic techniques. This article reviews some of the historical aspects of crossing vessels and explores recent studies that are starting to shed some light on this controversial topic.

Vessels around the ureteropelvic junction: significance and imaging by conventional radiology

We studied the influence of vessels crossing the ureteropelvic junction and of the grade of hydronephrosis in 86 patients who underwent endoureteropyelotomy. With a follow-up ranging from 1 to 12 years, the presence of crossing vessels had a significant negative influence on the outcome and recurrence rate of the procedure. The success rate was 82% when no vessels were present but only 33% when crossing vessels were documented. In 13 of 15 failures (87%), a crossing vessel was found at open pyeloplasty. The degree of hydronephrosis was a less potent detrimental factor, with an 81% success rate in low-grade and 54% in high-grade hydronephrosis. The best results (90% success) were obtained in patients with no crossing vessels and low-grade hydronephrosis and the worst (30% success) in those with high-grade hydronephrosis in the presence of crossing vessels. Selection of patients according to those prognostic factors is recommended. Conventional intravenous urographic imaging techniques proved insufficient, and only angiography provided diagnostic accuracy; less-invasive methods are desirable.

Crossing vessels at the ureteropelvic junction: do they influence endopyelotomy outcome?

The majority of crossing vessels probably are inconsequential. Bleeding should not be a concern if the incision is made laterally. The optimal way to improve endopyelotomy results is to determine which crossing vessels truly are significant, and the authors describe the clinical trial that might be carried out to answer the question.

Abnormal innervation and altered nerve growth factor messenger ribonucleic acid expression in ureteropelvic junction obstruction

The pathophysiology of ureteropelvic junction obstruction is unknown. Using specific antibodies, we studied specimens from 35 cases of ureteropelvic junction obstruction and 32 of normal ureteropelvic junction by immunohistochemistry using protein gene product 9.5 (a general neuronal marker), S100 (a supporting cell marker), synaptophysin (a neuromuscular junction marker) and nerve growth factor receptor. Nerve growth factor expression was examined at the messenger ribonucleic acid (mRNA) level using reverse transcription-polymerase chain reaction technique in 11 ureteropelvic junction obstruction specimens and 7 controls. The most striking finding was the marked reduction of protein gene product 9.5, synaptophysin and nerve growth factor receptor staining positive nerve fibers in the muscle layers of ureteropelvic junction obstruction compared to the normal ureteropelvic junction. Supporting nerve cell fibers (S100) were preserved in cases of ureteropelvic junction obstruction and normal ureteropelvic junction. A significantly less intense signal for nerve growth factor mRNA was found in the ureteropelvic junction obstruction specimens compared to normal ureteropelvic junction. These findings suggest that defective innervation may have an important role in the pathogenesis of ureteropelvic junction obstruction, and decreased nerve growth factor mRNA expression may be important in the etiology of ureteropelvic junction obstruction.

Late development of pelviureteric junction obstruction (PUJO) in a girl with previously normal pyelogram: a case report

A case of ureteropelvic junction obstruction in a girl with previously normal pyelogram is presented. The aetiology of this development is unclear but this report emphasizes the need for a close follow-up of patients with persistent flank pain even if the initial pyelograms are normal.

Three-D muscular arrangement at the ureteropelvic junction and its changes in congenital hydronephrosis: a stereo-morphometric study

Ureteral walls were obtained from twelve autopsies without urological diseases and from surgical material of twelve patients operated for congenital hydronephrosis. The specimens were submitted to computer-assisted analysis of 3-D muscular architecture at the ureteropelvic junction (UPJ). Serial histologic sections in parallel with the wall were prepared. A geometric model was introduced to simplify the muscular layer, replacing bundles with vectors of corresponding size and direction. The vector distribution visualized that normally, the ureteral muscles change their arrangement with age, from a circular pattern in neonates to an oblique mesh in adults. In addition, longitudinal muscles emerged at the age of two years in the subepithelial layer. In patients with congenital hydronephrosis, not only were such growth-related changes ambiguous or lacking, but there also were various abnormalities; segmental muscular hypoplasia, disarrangement of bundles or lack of longitudinal fibers. These were considered to closely correlate with the urinary obstruction in patients with this disease.

Ureteropelvic junction obstruction. I. Observations on the classic type in adults

A total of 111 adults underwent repair of congenital ureteropelvic junction obstruction during a 15-year period. A majority of the patients (77 per cent) presented with flank pain. In all patients established (89 per cent) or intermittent (11 per cent) hydronephrosis was demonstrated. In contrast with our former practice, a majority of the patients (86 per cent) underwent dismembered pyeloplasty with intubation. Of the 10 hypertensive patients 8 remained hypertensive postoperatively but only 3 of 22 patients with stones had recurrent calculi. The success rate was 95 per cent with 1 operation. Three patients required a second repair and 1 underwent nephrectomy. Therefore, the eventual success rate was 99 per cent.

Congenital Ureteropelvic Junction Obstruction: Abdominal Pain in Runners

In brief: This paper discusses ureteropelvic junction obstruction and presents a case report of a young male athlete with a 13-year history of vague abdominal pain associated with long-distance running. Ureteropelvic junction obstruction was found to be the cause of his pain. A review of similar cases showed a significant number of patients with vague abdominal pain produced by ureteropelvic junction obstruction. While IVP is the standard for diagnosis, ultrasonography can be a useful screening test. The authors conclude that ureteropelvic junction obstruction should be considered for patients with abdominal pain.

Changes in spontaneous ureteral peristalsis in experimental shock with and without administration of adrenaline during shock

In a control group of anaesthetized dogs, a reduction in the number and speed of peristaltic movements of the ureter was observed during anaphylactic and dye shock. In the second, experimental, group of dogs the effect during fully-developed shock of an intravenous injection of adrenaline at the maximum active dose on the ureter dynamics was investigated. It was found that adrenaline increased the number and, to an even greater extent, the speed of peristaltic movements over a period of a few minutes' duration during which the arterial pressure remained high. It seems that adrenaline first and foremost facilitates the conduction of peristaltic stimuli in the ureter.

A morphometric study of the pelvi-ureteric junction and review of the pathogenesis of upper ureteric obstruction

A morphometric analysis has been made of the normal human pelvi-ureteric junction and upper ureter. There was found to be no anatomically definable pelvi-ureteric junction. Muscle bundles of renal pelvis and upper ureter run a spiral course and do not form clear-cut layers. There is a great normal variation of thickness of the renal pelvic and ureteric muscularis, as well as of the total thickness of these structures. Smaller, but sometimes still large differences, are seen between right and left pelvi-ureteric specimens of individual patients. Suggested normal ranges of thickness are: (1) Renal pelvis: total thickness 340-1300 micrometers, muscularis 270-1100 micrometer. (2) Upper ureter: total thickness 450-1000 micrometer, muscularis 240-790 micrometer. No neurones are present in the renal pelvis or upper ureter. The possible etiologies of pelvi-ureteric obstruction are discussed.

Pyeloplasty: to divert or not to divert?

The use of diversion in conjunction with pyeloplasty has been a matter of continuous debate for a number of years. In consequence the matter has been left to the urologist's individual preferences with no objective data to support these preferences. Herein the authors present an analysis of 105 pyeloplasties performed by four surgeons over a period of eighteen years with a view to determine the place and type of diversion in relation to the surgical technique used and the long-term effects of such diversion or abstinence thereof.

Valves of the ureter as a cause of primary obstruction of the ureter: anatomic, embryologic and clinical aspects

The causes of obstruction of the ureter at the ureteropelvic and ureterovesical junctions are still controversial. In this study portions of obstructed ureters were excised at operation or autopsy and the suspected sites of obstruction were examined anatomically, radiographically and histologically. A valvular mechanism caused obstruction in 15 of 27 specimens. The valve lay at the junction of the dilated and undilated segments of the ureter. The internal anatomy of this site was hidden from external view by the fascia overlying the ureter and was demonstrated by contrast ureterograms. The axes of the lumina of the dilated and undilated segments were eccentric and the walls of the ureter overlapped at the site of obstruction to form a common wall, which created a valve effect. The valve flaps were visualized radiographically as a filling defect. The valve obstructed antegrade but not retrograde flow. Anatomic dissection or serial sections of blocks of the valve zone demonstrated that either a single or a double flap caused obstruction. The valve was coapted against the opposite wall of the distal segment by the pressure generated in the dilated ureter during antegrade flow. The muscle of the unobstructed segment of ureter distal to the valve appeared normal histologically, whereas the muscle of the obstructed proximal segment was hypertrophic.

Pediatric pyleoplasty

A series is reviewed of 153 pyeloplasties in 130 pediatric patients. Dismembering pyeloplasty was performed in most cases, usually with temporary nephrostomy drainage. A satisfactory anastomosis resulted in each case. The important technical aspects of pyeloplasty are emphasized.

Primary ureterocalycostomy for severe hydronephrosis in children

Fourteen children are described in whom primary ureterocalicostomy was performed for severe hydronephrosis due to pyeloureteral obstruction. Seven of them presented a horseshoe kidney. After a follow-up varying from 1 to 6 1/2 yr, clinical and radiologic improvement was obtained in 12 patients. Exclusion of decompensated renal pelvis and formation of strictly declivous drainage system, especially benefiaial in the case of horseshoe kidney, are two advantages of this procedure. The most important technical consideration is adequate resection of the renal cortex in order to free the large ureterocaliceal anastomosis from the surrounding cortical tissue. It is concluded that primary ureterocalicostomy is the operation of choice for hydronephrosis associated with a horseshoe kidney. This procedure is not advised, however, for simple though severe, hydronephrosis.

Functional pelviureteric junction obstruction

A case of functional pelviureteric junction obstruction is reported and a radiological method for detecting this entity is described. The causes of this condition are described and the reasons for the appropriate treatment are given.

Pelvioplasty--patient selection

An ever-increasing number of modalities provide diagnostic and predictive indicators for better patient selection in the treatment of ureteropelvic juncture obstruction. Contemporary histological studies and improved results have culminated in the selection of the dismembered pelvioplasty as the operation of choice. When the renal scan, renogram, renal biopsy or nitroblue tetrazolium studies are used fewer patients are subjected to a needless reconstructive operation. Dismembered pelvioplasty provides excision of the diseased ureter, reduction of pelvic redundancy and an opportunity for the "pacemaker" cells to function properly.

Ureteropelvic obstruction of duplex kidney

Herein is reported a case in which congenital ureteropelvic obstruction was complicated by renal duplication. A dismembered pyeloplasty requiring two anastomoses was performed.

Some observations and theories on the wide ureter and hydronephrosis

A simple but effective classification of the wide ureter is proposed. It separates ureters into two major groups of refluxing and non-refluxing, but emphasises that not all non-refluxing ureters are obstructed. An analysis is made of normal and abnormal ureteric peristalsis and the part it plays in conducting a bolus through the pelviureteric and ureterovesical junctions. A theory is advanced to explain the poor emptying of the wide ureter and the abnormal pelviureteric junction. It is based on the inability of the circular and longitudinal muscles to form a bolus and it explains how the unopposed and inadvertent contraction of the circular muscle grips the orifice in each situation to aggravate the poor emptying.